Earpiece or acoustic device.



No. 793,436. PATENTED JUNE 27, 1905.

' .P. c. GREEN. BARPIBGE 0R ACOUSTIC DEVIGE.

APPLICATION FILED NOV. 7, 1904.

Suvantoz Witmobfl I v p UNITED STATES Patented June 27, 1905.

PATENT OFFICE.

EARPIECE OR ACOUSTIC DEVICE.

SPECIFICATION forming part of Letters Patent N 0. 793,436, dated June 27, 1905.

Application filed November 7, 1904:. Serial No. 231,630.

T 0 all whom, it may concern.-

Be it known that I, PETER CHARLES GREEN, a citizen of the United States, residing in the city and county of Philadelphia, State of Penn sylvania, have invented a new and useful Earpiece or Acoustic Device, of which the following is a specification.

My invention consists of a .new construction of earpiece or acoustic device for telephone-receivers which is adapted to provide means for shutting off from the ear and re ceiver the outside sound -vibrations and is adapted to focus the sound-waves of the telephone-receiver, the effect of which is evident.

It further consists in providing suitable means for preventing condensation within said earpiece.

Figure 1 represents a perspective View of a telephone-receiver, showing the earpiece in position. Fig. 2 represents a partial side elevation and partial sectional view thereof.

Similar letters of reference indicate corresponding parts in the figures.

Referring to the drawings, I have found that in transmitting the sound-waves it is of advantage to bring the same to a focus at substantially a point adjacent the ear-drum in order that the sound will be intensified, and I have shown in the drawings an earpiece or acoustic device which is adapted for this purpose. It broadly consists of a hollow shell or tube which is formed to substantiallyfit the opening in the cap of an ordinary telephone-receiver now in use, and the bore of said shell is dome-shaped at a point substantially adjacent the end which is inserted in the ear of the user. In the walls of the shell I provide suitable small openings, preferably two, in order to permit circulation of the air on the interior of said shell in order to prevent condensation of air which would otherwise occur were it entirely confined between the diaphragm of the telephone-receiver and the tympanic member of the ear, and if this condensation did take place it would have the effect of increasing the tension on the said tympanic member, which would cause a feeling of fullness or pressure in the drum-cavity,

as well as decreasing the hearing sense or power. These openings, therefore, serve to maintain the equilibrium between the external air and the air contained within the shell, which, it is of course understood, is continuous, with the air of the external auditory canal when the device is in position. False vibrations and interference of outside sounds are also thus avoided. In addition the openings further serve to prevent aftervibration caused by the return or the reflection of the sound-waves.

In the drawings, therefore, A designates an ordinary telephone-receiver, having a cap B and the usual diaphragm C. In the opening of the cap is placed the shell or acoustic device D, which has curved sides and is secured in the opening, the inner end, however, being adapted to closely fit and engage the walls of said opening and in such a manner as not to interfere with the vibration of said diaphragm 0 when the cap is in position. The outer wall of the shell is tapered, as at E, in order to fit the external auditory canal of the ear, and the inner wall of the shell is domeshaped, as at Fthat is, near the outer opening in the tube or shell. By reason of this construction the sound-waves from the diaphragm pass through the tube or shell and are brought together by the dome-shaped.

wall F that is, to a focus at a point where the waves pass into the earthus intensifying the sound from the telephone-receiver, while the tapered outer end E fits closely the outer auditory canal, preventing the sound-vibrations and noises outside of the receiver from reaching the ear.

Gr designates openings suitably situated in the wall of the shell and which serve the purposes above explained of preventing air-condensation within the shell and at the same time preventing aftervibrations caused by the return or any reflected sound-wave.

The construction of the device stops the lateral diffusion of the sound-waves emanating from the telephone-receiver and carries them at the proper angles to be reflected and brought to a focus by the dome-shaped wall of the device at a point axial to the auditory canal, which is obviously that most advantageous to the perfect hearing.

The device is adapted to lit the human ear perfectly and exclude external noises, but is prevented from entering the ear-canal beyond a certain desired point, thus preventing injury and yet filling the ear completely. It is easily adjusted, simple in construction, and can be readily removed for cleansing and sterilizing.

It will be evident that various changes may be made by those skilled in the art which will come Within the scope of my invention, and I do not, therefore, desire to be limited to the exact construction herein shown and de-.

scribed.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a device of the character described, a shell apertured intermediate its ends and open at both ends, the bore of which shell, at one end, 1s dome-shaped, whereby the sound-waves are focused.

2. In a device of the character described, a.

PETER CHARLES GREEN.

Witnesses:

J OI-IN A. WVIEDERSHEIM, WM. CANER I/Vmnnnsnm. 

